jQuery: Concatenation Results in Undefined

I'm trying to display 10 opti开发者_如何转开发on tags in a select. The notaDt.text() is the current value. So if that value matches the i, the displays a "selected".

var n, select, option;              
for(var i=10; i>=1; i--) {  
    n = notaDt.text();
    select = ( i == n ? "selected" : "");
    option = option + '<option value="' + i + '" ' + select + ' >' + i + '</option>';
}

The problem is with the option = option + ... It returns " undefined" when it's called (as seen below), but everything works fine.

http://img821.imageshack.us/img821/2951/screenshot20101129at749.png

Are there any other concatenation methods I could try to not get this message? Thanks!

---

You need to start with an empty string for option, like this:

var n, select, option = "";  

Otherwise the first time you concatenate with option (at that point, being undefined) you get "undefined" to start your string off with, as you get the toString result of undefined.

---

You need to set option to an initial blank string - like this:

var n, select, option = "";

And why not use += instead of option = option + - that's just my opinion.

---

Initially option is undefined until the first concatenation. Why don't you set it initially to an empty string?

var n, select;
var option = "";
for(var i=10; i>=1; i--) {  
    n = notaDt.text();
    select = ( i == n ? "selected" : "");
    option = option + '<option value="' + i + '" ' + select + ' >' + i + '</option>';
}